using System;
namespace CH01
{
    class Test
    {
        static void Main()
        {
            Console.WriteLine("大家好，我是{0}，今年{1}岁","渣渣辉",20);

            Console.WriteLine("{0}",123.456789);
            Console.WriteLine("{0:f}",123.456789);
            Console.WriteLine("{0:f1}",123.456789);
        }
    }
}